Clamping device for an accurately located workpiece

ABSTRACT

A clamping device holds a workpiece in secured position by engaging the outer side walls thereof after the workpiece had been accurately located on a support from the inside surface thereof. After the workpiece is so located a plurality of spring pressed plungers independently move locking heads longitudinally and at an angle toward the workpiece side walls which are engaged thereby and which retains the workpiece in exact internal surface located position after the locating device is withdrawn.

United States Patent 1 Doocey Nov. 13, 1973 [5 CLAMPING DEVICE FOR AN2,432,137 12 1947 Burke 269/153 x ACCURATELY LOCATED WORKPIECE 3 22%?3/132;

: 9 Ole l Inventor: Robert J- D y pp Saddle 3,512,794 5 1970 Lohman269/138 River, NJ.

[73] Assignee: Standard Tool & Manufacturing Primary Examiner-Othell M.Simpson Co., Lyndhurst, N.J. Assistant Examiner-E. F. Desmond Filed Mar11 1971 Attorney-Harness, Dickey & Pierce l. N 2 268 [211 App 0 1 57ABSTRACT [52] U s Cl 269/153 269/137 269/224 A clamping device holds aworkpiece in secured posi- 279 I121 tion by engaging the outer sidewalls thereof after the [51] Int Cl B23, 31/10 B251) H08 workpiece hadbeen accurately located on a support [58] 269/85 104 107 from the insidesurface thereof. After the workpiece is 269/138 v so located a pluralityof spring pressed plungers inde- 5 6 121 pendently move locking headslongitudinally and at an angle toward the workpiece side walls which areen- [56] References Cited gaged thereby and which retains the workpiecein UNITED STATES PATENTS exact internal surface located position afterthe locating device is withdrawn. 3,633,929 l/1972 Morawski et al.279/60 X I 3,248,122 4/1966 Roddy 269/137 UX 8 Claims, 4 Drawing Figuresn 1"; 1 if I \I.' 1 L 1 L l :J V M j Z/ Z] lj/ PATENTEUmvmm 3771.780SHEET 1t? 3 I NVEN TOR.

PAIENIEUNuv 13 m5 SHEET 2 [IF 3 M;- y M a SUMMARY OF THE INVENTION Theinvention pertains to a clamping device having a plurality of springpressed plungers located in sloping angular positions about thecenterline of the device. The forward diverging ends of the plungershave a head thereon with a clamping face which will move toward theworkpiece wall when the springs move the plungers and heads to the rear.A plurality of the clamping devices are mounted on a rotatable tablewhich is angularly advanced in equal angular increments to have thedevices located seriatim at different machine stations and at loadingand unloading stations. The workpiece is a cup-like element on whichwork operations are to be performed located from the interior surfacethereof.

At the loading and unloading stations a ram actuates a head whichadvances the plungers of two adjacent stations, one of which releases aworkpiece while the other of which receives a workpiece. The receivedworkpiece is accurately located on a head of a supporting ram which isadvanced thereby to accurately locate the workpiece on the support ofthe device. Upon the reversal of the ram which advanced the plungers,the plungers are free to be retracted by the individual springs whichmoves the heads rearwardly and towards the side wall of the workpiece tograsp the workpiece in the position in which it was located from theinterior surface thereof. The work supporting head is retracted by itsram and the table isadvanced so that drilling, reaming, facing and otheroperations can be performed seriatim on the workpieces supported on theplurality of the clamping devices.

' BRIEF DESCRIPTION OF THE DRAWINGS 'FIG. 3is a sectional view of thestructure illustrated in FIG. 2, taken on theline 3'3 thereof, and

FIG.'4 is a view of the structure illustrated in FIG. 1, with theworkpiece advanced and accurately Iocatedby a reciprocal supportingstructure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A table 11 has a plurality ofclamping devices 12 mounted thereon which support a workpiece 13 on theouter faces thereof. The table is rotated about its center in incrementsto move the devices 12 from one work station to another until theworkpiece is removed at'an unloading station after being machined. Theunloaded device 12 is advanced to a loading station where a newworkpiece to be machined is accurately located and clamped to thedevice. Each device 12 has a housing 14 which is secured by screws 15 tothe table. In the device herein illustrated, seven holes 16 are boredthrough the body at an angle of approximately 7 to have the centerlinesconverge rearwardly toward the centerline of the device. Each bore 16has a sleeve I 18 secured therein by the head of a screw 19 while beingsealed to a plunger 21 mounted therein by sealing rings 22. The outerend of the plunger 21 supports a head 23 located 2 thereon by a dowel 24and secured thereto by a screw 25.

The heads 23 are cylindrical and are provided with a flat face 26machined at the angle at which the plungers are located so as to beparallel to the wall of the workpiece 13. The plunger is hollow forreceiving a spring 27 engaged by spacers 28 at each end one abutting thebottom of the aperture 29 the opposite one abutting a pin 31 whichextends through a slot 32 in the plunger into apertures 33 in the sleeve18. The flat faces 26 of the heads 23 surround the workpiece 13 inposition to move inward when the plungers 21 are retracted by thesprings 27 to be operated individually -into engagement with the outersurface of the side wall 34 of the workpiece. Locating pins 35 extendoutwardly from the outer face of the device for aligning the locatingand machine heads relative thereto at a station to which the device wasadvanced.

The plungers 21 extend rearwardly from the housing 14 in position to bemoved forwardly at the unloading station 36 and the adjacent loadingstation 37 by plates 1 38 mounted on a head 39. The head 39 has a pairof sleeves 41 extending rearwardly thereof in which slide rods 42 aresecured by set screws 43. The rods are mounted in bearings 44 inbushings '45 which are supported on a platform 46 on a base 47 which issecured to the table 11. The bearings 44 are retained within thebushings 45 by set screws 48. A ram 49 is mounted on the platform 46having its pistonrod 51 secured to the head 39 by a screw 52 having itshead located within a T-slot 53. When the head 39 is moved forwardly bythe outward movement of the piston rod 51 the plates 38 advanceoutwardly to engage the plungers 21 of the two adjacent devices 12 atthe unloading and loading stations 36 and 37. The movementof theplungers outwardly moves the heads 23 outwardly and the faces 26 thereofaway from the wall 34 of the finished workpiece at the unloading station36 to permit it to be removed. The outward movement of the heads 23 atthe loading.statio n 37. permits a workpiece to be machined to be.move dinto engagement with the device. v

A plate 54 is secured to the platform 46 by screws 5 g to extendupwardly and forwardly as illustrated in FIGS. 1 and 4 forsupporting apair of switches The head 39 supports an arm 57on which screws58 and 59are adjustably mountedThe screw 58 operates an arm 61 on one of theswitches 56 when the head 39 is in advanced position while the head ofthe screw 59 engages an arm 62 on the other switch 56 when the head 39is At the loading station a piston rod 63 of a ram 64 carries a head 65having an exterior face which accurately locates the workpiece 13thereon. Pivoted spring pressed-fingers 69 hold the workpiece on the endof the head 65 in a manner to permit the heads 23 to moveinto'engagement with the workpiece 13. The head65 has a downwardlyextending arm 66 to which a square rod'67 is secured for passing througha square aperture in spaced blocks 68 located below the ram 64. The rodprevents the piston rod 63 from turning to thereby accurately locate theworkpiece against the clamping device 12 aided by the engagement of apair of sockets 70 on the end of a spring pressed crossmember on thehead 65 with the locating pins 35. The workpiece 13 has twoscrew-receiving apertured recesses which rest on the ends of arms 71 ofa U- shaped element 72 which is secured to theouter face of the housing14 by screws 73. A locatingpin 74 is mounted above the element 72 inposition to extend into a screw-receiving recess 75 through which a holeis to be drilled. An aperture 76 of greater diameter than that of thehole to be drilled extends into the end of the pin 74, the front face ofwhich may be relieved ,at 77 to prevent interference with the wall ofthe screwreceiving recess 75. The advancement of the head 65 by the ram64 moves the workpiece 13 against the ends of the pin 74 and arms 71 andaccurately locates it thereon when the sockets 70 engage the locatingpins 35. The rearward movement of the head 39 permits the plungers 21 tobe retracted by their individual springs 27 drawing the heads 23rearwardly along-the converging angular pathswhich move the faces 26inwardly into engagement with the outer surface of the wall 34 of theworkpiece 13. This clamps the workpiece on the supporting pin 72 andarms 71 exactly in the position it is held by the head 65 located fromthe internal surface of the workpiece.

Thereafter the piston rod 63 is retracted by the ram 64 and the table 11is advanced angularly to move the clamping device 12 and the securedworkpiece to the next adjacent section. A pair of limit switches (notshown) are actuated by the ram 64 at the end of its forward and rearwardmovements in the same manner as the ram 49 actuates the switches 56. Atthe stations, holes may be drilled in the workpiece 13 from the insidethereof and the hole 78 reamed, the outer edge 79 can be faced and anyother machine operations may be performed at the various machiningstations to which the clamping devices 12 are advanced.

Each time the piston rod 51 of the ram 49 is advanced, a finishedworkpiece is removed from the device at the unloading station 36 and anew workpiece clamped in the device at the loading station 37. After theworkpiece 13 is located by the head 65, the retraction of the head 39permits the plungers 21 to move the flat faces 26 of the heads 23 intoclamp ng engagement with the outer surface of the wall 34 of theworkpiece. The heads 23 are retracted the same or different amountsdepending upon the location of the outer surface of the workpiece wall.The workpiece 13 is clamped in this manner on the supporting pin 72 andarms 71 when accurately held thereon by the head 65 which locates theworkpiece from the internal surface thereof.

said heads, reciprocal means at the rear of the housing spaced from saidplungers, and means for advancing said reciprocating means intoengagement with said plungers for moving the plungers forwardly toworkpiece disengaged position while compressing said spring means.

2. In a clamping device as recited in claim 1, wherein workpiecelocating means accurately positions the workpiece between the plungerheads when in forward position to permit the heads to be individuallymoved by said spring means to engage the outer surface of the workpiecein the position it is held as said reciprocal means is moved fromengagement with said plungers.

3. In a clamping device as recited in claim 2, wherein the workpiece issupported on the locating means by the engagement of the internalsurface thereof.

4. In a clamping device as recited in claim 3, wherein the workpiece iscuplike in shape supported by its internal surface on the locating meanswith its outer surface engaged by the plunger heads during the time theworkpiece is accurately located.

5. In a clamping device, a support, a plurality of plungers having fixedheads thereon mounted on said support about stop means against which aworkpiece is to be supported, ram 'means for supporting a cupshapedworkpiece having a sidewall and a bottom by its inner surface andadvancing it to a position between said heads until the bottom engagessaid stop means, springs on each said plunger which individually movethe heads to engage the outer surface of the workpiece in the positionretained by said ram means to permit machining to be performed on theinside of the workpiece when the ram means is removed, said plungersconverging toward the rear of said support, said heads having workpieceengaging surfaces presented theretoward, and means for advancing saidplungers forwardly to compress the-springs and release a workpiece, eachplunger being retracted by its spring when the advancing means isretracted to cause the engaging surfaces on the heads to move rearwardlyand toward the workpiece the amount necessary to move into engagementtherewith for clamping the workpiece in the position in which it isheld.

6. In a clamping device as recited in claim 5, wherein means areprovided for retracting the ram means and moving it away from theworkpiece after the workpiece is clamped to the device.

7. In a clamping device as recited in claim 5, wherein the ram means hasa supporting head for the workpiece, sockets on said head havinganaperture presenting forwardly, and pins on said support engaged bysaid apertures for accurately locating the workpiece when moved againstthe support.

8. In a clamping device as recited in claim 7, wherein a ram moves theplungers and heads forwardly to release a workpiece at an unloadingstation, said ram also moving the plungers and heads forwardly at anadjacent loading station permitting a finished workpiece to be removedand a workpiece to be machined to be clamped.

1. In a clamping device for a workpiece, a housing, a plurality ofspaced plungers carried by said housing about the center line thereofextending therefrom and converging rearwardly theretoward, spring meanscarried by said plungers urging them toward the rear, heads on theforward portion of the plungers each having an engaging surfacepresented toward the workpiece, support means for the workpiece on thefront of the housing for positioning said workpiece between said heads,reciprocal means at the rear of the housing spaced from said plungers,and means for advancing said reciprocating means into engagement withsaid plungers for moving the plungers forwardly to workpiece disengagedposition while compressing said spring means.
 2. In a clamping device asrecited in claim 1, wherein workpiece locating means accuratelypositions the workpiece between the plunger heads when in forwardposition to permit the heads to be individually moved by said springmeans to engage the outer surface of the workpiece in the position it isheld as said reciprocal means is moved from engagement with saidplungers.
 3. In a clamping device as recited in claim 2, wherein theworkpiece is supported on the locating means by the engagement of theinternal surface thereof.
 4. In a clamping device as recited in claim 3,wherein the workpiece is cuplike in shape supported by its internalsurface on the locating means with its outer surface engaged by theplunger heads during the time the workpiece is accurately located.
 5. Ina clamping device, a support, a plurality of plungers having fixed headsthereon mounted on said support about stop means against which aworkpiece is to be supported, ram means for supporting a cup-shapedworkpiece having a sidewall and a bottom by its inner surface andadvancing it to a position between said heads until the bottom engagessaid stop means, springs on each said plunger which individually movethe heads to engage the outer surface of the workpiece in the positionretained by said ram means to permit machining to be performed on theinside of the workpiece when the ram means is removed, said plungersconverging toward the rear of said support, said heads having workpieceengaging surfaces presented theretoward, and means for advancing saidplungers forwardly to compress the springs and release a workpiece, eachplunger being retracted by its spring when the advancing means isretracted to cause the engaging surfaces on the heads to move rearwardlyand toward the workpiece the amount necessary to move into engagementtherewith for clamping the workpiece in the position in which it isheld.
 6. In a clamping device as recited in claim 5, wherein means areprovided for retracting the ram means and moving it away from theworkpiece after the workpiece is clamped to the device.
 7. In a clampingdevice as recited in claim 5, wherein the ram means has a supportinghead for the workpiece, sockets on said head having an aperturepresenting forwardly, and pins on said support engaged by said aperturesfor accurately locating the workpiece when moved against the support. 8.In a clamping device as recited in claim 7, wherein a ram moves theplungers and heads forwardly to release a workpiece at an unloadingstation, said ram also moving the plungers and heads forwardly at anadjacent loading station permitting a finished workpiece to be removedand a workpiece to be machined to be clamped.